Title :
InAlAs/InGaAs HBT exponentially graded base doping and graded InGaAlAs emitter-base junction
Author :
Tran, L. ; Streit, D. ; Kobayashi, K. ; Velebir, J. ; Bui, S. ; Oki, A.
Author_Institution :
TRW, Redondo Beach, CA, USA
Abstract :
The authors report high-performance InAlAs/InGaAs heterojunction bipolar transistors with base doping graded exponentially from 5*10/sup 18/ cm/sup -3/ at the collector junction to 5*10/sup 19/ cm/sup -3/ at the emitter junction. The built-in field reduces the base transit time and results in 20% and 30% improvement in cutoff frequency f/sub t/ and maximum oscillation frequency f/sub max/, respectively, compared to devices with uniformly doped base. For 1- mu m emitter devices, f/sub t/ of 65 GHz and f/sub max/ of 120 GHz were obtained. A graded InGaAlAs emitter-base junction is also incorporated which results in lower V/sub be/ and higher beta compared to abrupt junction devices.<>
Keywords :
III-V semiconductors; aluminium compounds; doping profiles; gallium arsenide; heterojunction bipolar transistors; indium compounds; solid-state microwave devices; 1 micron; 120 GHz; 65 GHz; InAlAs/InGaAs HBT exponentially graded base doping; InGaAs-InAlAs-InGaAlAs; base transit time; built-in field; collector junction; cutoff frequency; graded InGaAlAs emitter-base junction; high-performance; maximum oscillation frequency; Cutoff frequency; Doping; Gallium arsenide; Heterojunction bipolar transistors; Indium compounds; Indium gallium arsenide; Indium phosphide; Molecular beam epitaxial growth; Substrates; Voltage;
Conference_Titel :
Indium Phosphide and Related Materials, 1992., Fourth International Conference on
Conference_Location :
Newport, RI, USA
Print_ISBN :
0-7803-0522-1
DOI :
10.1109/ICIPRM.1992.235570
